Just what is gluten, anyway? If you are a baker, or if you have to keep it out of your diet, or both, it may be helpful to know.
Gluten is the common name for a complex of 2 types of proteins that is found in wheat, rye, and barley, with very similar proteins in oats. (See Are Oats Gluten Free?) It is responsible for the structure in bread dough that makes yeast breads possible. Skip to Gluten’s Role In Bread Making
Only the Prolamin-Glutelin complexes in wheat, rye and barley are considered to be gluten in current definitions. But oat prolamins and glutelins are similar in some respects, and some people with gluten intolerance or sensitivity are sensitive or intolerant of oats as well. (See Are Oats Gluten Free?)
Grains that don’t contain gluten and why: Teff, millet, rice, corn, buckwheat, and sorghum, have prolamins and glutelins that are made up of different amino acid sequences that aren’t considered to be gluten. These grains don’t cause a reaction in gluten sensitive people.
Specifically it’s amino acid sequences in the prolamin, a component of gluten, that cause the reaction. The prolamins are named gliadin in wheat, secalin in rye, or hordein in barley. (And for some people, avenin in oats.) The disease is only present if you are genetically susceptible and the conditions in your intestines allow the response.
For other people gluten causes other problems, collectively known as gluten sensitivity, or sometimes gluten intolerance. Some of these people may have undiagnosed Celiac Disease, as it can be difficult to get a confirmed diagnosis.
Gluten allergies are another type of sensitivity. (Wheat allergies may be totally different–often a person with a wheat allergy is allergic to different proteins in wheat.)
When bread dough is kneaded, the gluten stretches and forms a net-like structure that allows the bread to rise.
It gives it the texture that holds the bread together so it doesn’t crumble like cakes and cookies or quick breads (think banana bread).
Without it sandwiches are a little difficult. (Although many creative people have come up with new ways to make good bread without gluten.)
It works because the gluten strands have properties that allow them to stretch without breaking, and to stick together in enough ways that it forms little bubbles.
When the yeast grows and consumes the sugar in the bread dough (either added sugar, or sugar from the grain) it gives off carbon dioxide, which blows up the gluten bubbles like little balloons that are all stuck together.
When the dough is heated in baking, the yeast dies and the gluten and other parts of the flour dry out, somewhat anyway, so you end up with a loaf of bread.